Unexpected o → n migration of the methyl group in 5-methoxy-6-cyanobenzimidazo-[1,2-a][1,8]naphthyridine

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 273–274, February, 1989.     

Cross-dehydrogenative coupling strategy for phosphonation and cyanation of secondary N-alkyl anilines by employing 2,3-dichloro-5,6-dicyanobenzoquinone

The cross-dehydrogenative coupling strategy for metal-free phosphonation and cyanation of secondary N-alkyl anilines has been developed firstly under mild reaction conditions. Based on detailed optimization of reaction conditions, the substrate generality of N-alkyl anilines and various hydrogen phosphonates has been investigated, and a series of versatile α-aminophosphonates and α-aminonitriles were therefore furnished in good to excellent yields. A plausible collective reaction mechanism through dehydrogenation to imine formation, then to respective α-aminophosphonates and α-aminonitriles was proposed.     

Magneto-hydrodynamical numerical simulation of heat transfer in MHD stagnation point flow of Cross fluid model towards a stretched surface

Here formulation and computations are presented to introduce the novel concept of activation energy in chemically reacting stagnation point flow towards a stretching sheet. Constitutive expression for Cross liquid is taken into account. Magnetic field is utilised in the transverse direction. Application of suitable variables generates the non-linear differential systems. Numerical solution by Runge–Kutta–Fehlberg approach is presented. Characteristics for the significant variables like Weissenberg number, Hartmann number, Schmidt number, activation energy chemical reaction parameter, velocity ratio parameter and Prandtl number on the physical quantities are addressed through graphs and tables. Our computations reveal that species concentration rises via larger activation energy parameter whereas it decays when Schmidt number is incremented. The Weissenberg number has opposite characteristics for local Nusselt and Sherwood numbers when compared with surface drag force.     

Simulation of magnetic dipole on gyrotactic ferromagnetic fluid flow with nonlinear thermal radiation

Journal of Thermal Analysis and Calorimetry - The present paper explores the features of thermal radiation on ferromagnetic Jeffrey fluid flow within the frame of gyrotactic microorganisms and...     

Author Correction: Drier Climatic Conditions Increase Withanolide Content of Withania coagulans Enhancing its Inhibitory Potential against Human Prostate Cancer Cells

Applied Biochemistry and Biotechnology - The original version of this article unfortunately contained a mistake in the image of Figure 1 and in Table 4. The corrected version of the figure...     

Fabrication and characterization of amidoxime-functionalized silica decorated with copper: a catalytic assembly for rapid reduction of dyes

In this study, amidoxime-functionalized silica decorated with copper (AFS-Cu) was fabricated and tested for its catalytic application. Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were employed to characterize its structure and morphology. The application of AFS-Cu as a catalyst for the catalytic reduction of methylene blue (MB) in aqueous media using NaBH₄ as reductant was evaluated. The ability to reuse as well as the effect of catalyst dose and pH of solution on the catalytic activity was investigated. The reduction of MB followed pseudo-first-order kinetics and the rate constant (k) was 0.6224 min^-1. AFS-Cu was found to be a highly effective catalyst for MB reduction reaction and can be easily recovered and reused several times with no appreciable loss of catalytic activity.     

Inhibitory effects of phylligenin and quebrachitol isolated from Mitrephora vulpina on platelet activating factor receptor binding and platelet aggregation

Phylligenine, together with quebrachitol, stigmasterol and two aporphine alkaloids--oxoputerine and liriodenine--were isolated from the twigs of Mitrephora vulpina C.E.C. Fisch. They were evaluated for their ability to inhibit platelet activating factor (PAF) receptor binding to rabbit platelets using 3H-PAF as a ligand and their antiplatelet aggregation effect in human whole blood induced by arachidonic acid (AA), collagen and adenosine diphosphate (ADP). Of all the compounds tested, phylligenin and quebrachitol exhibited potent and concentration-dependent inhibitory effects on PAF receptor binding, with IC(50) values of 13.1 and 42.2 μM, respectively. The IC(50) value of phylligenin was comparable to that of cedrol (10.2 μM), a potent PAF antagonist. Phylligenin also showed strong dose-dependent inhibitory activity on platelet aggregation induced by AA and ADP.     

Circular neighbor-balanced designs using cyclic shifts

In agriculture experiments, the response on a given plot may be affected by the treatments on neighboring plots as well as by the treatments applied to that plot. In this paper we consider such type of situations and construct circular neighbor-balanced designs (CNBDs) by the method of cyclic shifts or sets of shifts. An important feature of this method is that the properties of a design can be easily obtained from the sets of shifts instead of constructing the actual blocks of the design. That is, the off-...     

Xanthine oxidase inhibiting flavonol glycoside from Amberboa ramosa

A new flavonol glycoside (1) has been isolated from the ethyl acetate soluble fraction of Amberboa ramosa and assigned the structure 5,7,4'-trihydroxy-3,8-dimethoxylflavone 5-O-beta-D-gluco-pyranoside (1). In addition, 6,4'-dihydroxy-3,5,7-trimethoxyflavone (2), 5,7-dihydroxy-4'-methoxyflavone (3) and (23R)-5alpha-cycloart-24-ene-3beta,21,23-triol (4) have also been reported for the first time from this species. The structures were deduced on the basis of 1D and 2D NMR techniques. The compounds 1-3 displayed weak to moderate inhibition against the xanthine oxidase enzyme.